The present invention relates to a multi-type CD player which can reproduce various types of discs such as a compact disc (CD) and a CD-ROM.
FIG. 5 shows a conventional multi-type CD player.
A disc 1 is secured to a spindle of a motor 13 to be rotated by the motor.
A pickup head 2 reads out the recording surface of the disc 1 and produces a reproduced RF signal which is supplied to an RF amplifier 3. In the RF amplifier 3, the RF signal is amplified and the amplified signal is supplied to a signal processor 6 for decoding the signal. The decoded signal is supplied to a DAC 7 where the signal is converted into an analog signal to produce an audio signal through a muting circuit 9.
The RF amplifier 3 further produces focus and tracking error signals which is applied to a driver 4. The driver 4 controls focusing and tracking operations of the pickup head 2 based on the error signals through a servomechanism 5.
The signal processor 6 produces a signal based on a sub-code recorded on a TOC (table of content) area of the disc 1. The signal is applied to a controller 10 for controlling the motor 13 through a spindle servo 12.
When a CD is reproduced, the controller 10 discriminates the CD based on a sub-code recorded on a TOC area of the CD decoded at the signal processor 6 to turn off the muting circuit 9.
When a CD-ROM is reproduced, the controller 10 discriminates the CD-ROM from the CD based on a sub-code recorded on a TOC area of the CD-ROM decoded at the signal processor 6. The controller 10 controls a display of a display-operation section 11 based on a control data for a computer.
The reproduced signal of the CD-ROM is higher than 20 kHz. If such a high frequency signal is output through the DAC 7, it causes noises. Therefore, when the CD-ROM is discriminated, the controller 10 controls to turn on the muting circuit 9 so as to reduce the noises.
However, if a muting characteristic of the muting circuit 9 is low, the noises are not sufficiently reduced. Accordingly, when the CD-ROM is reproduced and even if the muting circuit 9 is turned on, the signal may be produced as noises because of insufficient muting operation.